This volume continues the mission of the series in providing a systematic and state-of-the-art overview of major research and development trends in peptide and protein science. Unlike many books and periodical reviews, this series, since its inception back in 1969, aims to cover different areas of the field irrespective of their popularity or immediacy index including those that had limited coverage in recent years. Each volume reviews literature predominantly published over the last two–three years and outlines background concepts that underpin fundamental, emerging and evolving disciplines and technologies. This approach is integral to each chapter in the series which grants each volume with a unique perspective allowing the monitoring of specific advances in discrete subject areas while keeping touch with foundations.

This 40th volume opens with a chapter reviewing the essence of peptide and protein science – peptide bond formation (Crisma, Formaggio, Toniolo). The chapter is offered as a critical discussion that is built around reaction mechanisms in the context of reactivity and regiospecificity of peptide bond formation. Five major classes of C-component reactive derivatives of amino acids and peptides are cross-compared including fluorides, anhydrides, esters, azides and amides. The comparison is based on 3D X-ray structures of the derivatives and tackles the persistent issues of chemical and optical homogeneity of the reaction. Of direct relevance to the efficiency of peptide synthesis appears the problem of developing derivatization reagents for the quantitative analysis of post-translational modifications – capabilities that are increasingly needed for modern “omics” approaches. This is the focus of a following chapter (Stefanowicz, Kluczyk, Szewczuk) which reviews the criticality of determining amino-acid sequences to understand biological processes at the molecular level. The chapter describes how mass spectrometry analysis combined with chemical modifications has been and is advancing proteome research. A specific emphasis is made on soft ionization techniques and targets for chemical tagging including experimental and more traditional strategies. Derivatisation reagents are categorised in terms of proton affinity, charge, chemical and enzymatic methods and in relation to target functional groups (thiols, amines, carboxyls). Pros and cons of label-free methods and isotopic labelling are discussed from the perspective of analytical reproducibility and precision as well as methods applicable for direct analysis in biological media. A step forward towards the biotechnological developments of amino-acid labelling is taken in the next two chapters. In one (Sisido, Fukuda, Shingai, Kitamatsu, Sasamoto), a particular emphasis is placed on the application of fluorescently labelled amino acids for screening cancer-cell binding peptides in situ and in vivo. The chapter describes different peptide screening protocols and compares their efficiency in in-solution and on-substrate formats. Experimental methodologies including higher order screening and the solubility optimisation of selected sequences are given for detailed searches of peptide libraries and sub-libraries of short peptide units in a variety of cultured cells and in vivo. Another chapter (Orosz and Csik) instead looks into direct therapeutic effects of a new class of molecular modalities, photosensitizers, which induce oxidative damages of cellular membranes and therefore hold promise in medicine. Usually referred to as photodynamic therapy, the strategy fully relies on photosensitiser conjugates with peptides and proteins and, by association, on the efficiency of the conjugation. The latter forms the bedrock of the discussion and highlights synthesis strategies, types of peptide carriers, from oligopeptide sensors and proteins to nanoscale conjugates, and their specific application targets. Photochemotherapy forms another substantial part of the discussion and focuses on antimicrobial and anticancer approaches including a contemporary reference to bioactive peptide sequences. The review of antimicrobial approaches takes an ultimate turn in the next chapter which explains the impact peptides and proteins have on the treatment and diagnosis of M. tuberculosis infections (Bosze and Hudecz). Here a disease-centric focus is matched by a comprehensive coverage of the problem with a particular attention given to methodologies and tools that enable the discovery of new biomarkers and peptide-based therapies. The challenges of epitope mapping, genomic and in silico methods as well as in vitro, ex vivo and in vivo validation of identified epitopes and proteins are combined in one coherent discussion. By acknowledging the nature of the bacterium the chapter guides the reader through key developments of immunodiagnostic assays in accord with new epitope selections. M. tuberculosis peptidomes and proteomes are classified according to cell epitope regions (T cells, B cells) while epitopes are presented in structural categories of linear peptides, conjugates, nanostructures and epitope-containing fusion proteins. The review culminates with applications including cell targeting, vaccine development and diagnostics. A specialist role of nanotechnology highlighted throughout this volume crystalises in the last chapter (De Santis, Ryadnov) which explores inter-relationships between peptide sequence, folding and self-assembly for the construction of self-assembling motifs and their products – nanoscale materials. Four major material forms are described with each provided with established examples. As the discussion develops the importance of commercialisation of peptide self-assembled materials becomes apparent and its near future prospects are reviewed in comparison to non-peptide materials derived from other and somewhat more traditional molecular classes. A variety of applications ranging from antimicrobials to nanoscale vectors for gene therapy and extracellular matrices for regenerative medicine closes up the volume.

To sum up, each chapter is structured to give as contemporary a coverage as practical while allowing for comparisons of existing concepts and approaches. Each provides an outlook of likely future develops and perspectives as a part of discussion or summary. The chapters are written by leading scientists in their respective domains which ensures expert-enabled access to a worldwide information source of broad appeal to research organisations and industry.

We wish to dedicate this volume to the former co-editor of the series Professor Etelka Farkas (Debrecen University, Hungary). We thank her for all her diligent work to enable the resurrection of this series and for her outstanding contributions to maintain the high standard of the SPR.